Field
The disclosed concept pertains generally to press systems and, in particular, to press systems such as, for example, conversion presses. The disclosed concept also pertains to vacuum port assemblies for press systems.
Background Information
Press systems, such as for example, conversion presses, are used in the can-making industry to form (e.g., convert and finish) partially formed ends or shells into fully finished can ends or lids such as, for example, easy open ends (EOEs) for food or beer/beverage containers.
Typically, the shells enter the press on a conveyor belt where they are progressively formed by a number of die assemblies. It is necessary to establish and maintain the desired position of the shells throughout the loading and metal forming processes in the press system, in order to properly form the EOEs. Some press systems employ vacuum pressure to hold and maintain the shells during these processes, wherein the vacuum pressure is typically provided using a plurality of airflow generators (e.g., regenerative blowers), and a network of conduits and/or ducting that is connected to a vacuum manifold on each die assembly via a number of vacuum ports on the side of the vacuum manifold, the ends of the vacuum manifold, and/or from beneath the die assembly.
There are a variety of disadvantages with all of these known vacuum port configurations. Among other problems, porting from beneath the die assembly requires machining of the lower die shoe to form an integral duct through the die shoe, and presents access problems during maintenance cycles. This configuration is also susceptible to gravity-related issues, such as airflow restriction or blockage due to the accumulation of debris at or about the port or integral die shoe duct. Porting through the sides of the vacuum manifold also poses maintenance problems, and airflow restrictions due to size limitations. That is, the port size (e.g., diameter) is restricted by the height or available space on the side of the vacuum manifold. This height limitation necessitates use of either smaller diameter ports, or ports having a transitioned structure (e.g., smaller inlet tapering to a larger outlet). This can restrict airflow and negatively impact the differential pressure capability of the airflow generator.
FIG. 1 shows an example die assembly 2 including a lower die shoe 4, and a vacuum manifold 6 mounted on the lower die shoe 4. The die assembly 2 includes three vacuum ports 8,10,12. A first vacuum port 8 extends outwardly from the lower die shoe 4 and is in fluid communication with a conduit or channel 14 (FIG. 2) that is machined through the lower die shoe 4 creating an integral passageway to the underside of the vacuum manifold 6, as shown in FIG. 2. The other two vacuum ports 10,12 are both substantially identical and extend outwardly from the side of the vacuum manifold 6 at opposite ends of the vacuum manifold 6, as shown in FIG. 1.
As shown in the section view of FIG. 2, the inner diameter 16 of the lower vacuum port 8 is generally the same as the diameter 18 of the integral conduit 14. That is, the diameters 16,18 are generally restricted by the space available for machining the integral conduit 14 in the lower die shoe 4. Additionally, the integral conduit 14 is disposed internal to the die shoe 4 and at a low point making it susceptible to the aforementioned access and gravity-related airflow problems.
FIG. 3 shows a section view of vacuum port 12, which is substantially similar to vacuum port 10 (FIG. 1). As shown, the diameter 20 of the inlet end 22 is restricted in size by the height 24 of the vacuum manifold 6. Thus, it is necessary to provide the vacuum port 12 with the tapered configuration shown, wherein the outlet end 26 tapers to the smaller inlet end 22, in order to fit within the restricted available space on the side of the vacuum manifold 6.
There is, therefore, room for improvement in press systems and in vacuum port assemblies therefor.